The present invention relates to orthopedic pin insertion tools of the type used to insert pins in bones to aid healing.
Veterinarians are often called upon to reset broken bones or perform surgical procedure in which bone structure is altered. These procedures and other procedures sometimes involve the insertion of a pin into the bone structure to immobilize portions of the bone with respect to one another or otherwise aid healing or provide structural support. Pins are available in a variety of diameters and with various tip designs. Some pins have smooth tips while others have partially threaded tips to aid in insertion and retention. Conventionally, pins are inserted with either a power tool or hand chuck. A hand chuck consists of standard chuck as one would see on a household power drill connected coaxially to a handle having a passage along its axis. An extension is sometimes provided on the handle at the end opposite the chuck. This entire assembly is sterilized, the pin is sterilized and the pin is inserted into the hand chuck with portions extending forward from the chuck and the rest being contained within the chuck and the handle and extension attached to the chuck. The chuck is tightened with a chuck key and the surgeon can then insert the pin by guiding it, turning it and applying pressure with the handle attached to the chuck. When the pin is properly positioned, the chuck is loosened, the tool removed, and the remaining pin cut-off. The axis of the chuck, the handle and the extension are all hollow providing an axial passage through the entire ensemble. This allowed the hand chuck to be used with long pin blanks.
Alternatively in the prior art, a low speed power drill was used to insert pins. The drill motor was provided with a removable extension which could be attached to the power output stud of the drill motor. The extension was in turn attached to a chuck. The extension had a blind passage extending along the axis of the extension coaxial with axis of the chuck. The extension passage had to be blind to protect the pin from the drill motor which could not be sterilized with conventional steam sterilization. A sterile shroud was placed around the drill motor, the sterile extension and chuck attached to the drill motor and the sterile pin inserted. The drill motor could then be used to guide, rotate and apply pressure to the pin inserting it as desired by the surgeon. When the pin was at the desired location, the chuck could be loosened, and the drill motor chuck assembly removed from the pin. The pin was then cut-off and the surgeon proceeded.
One cannot conveniently sterilize an electric drill motor. Therefore, prior art extensions for use with a drill motor had an aperture on one end to connect with the drill motor and a passage on the other end allowing intrusion of the pin into the extension. These two passages were not connected but were isolated one from the other. The extension to be attached to the drill motor was fabricated to close tolerances and shorter than the handle used with a hand chuck. This was necessary to prevent wobbling and to keep the pin coaxial and under control by the electric drill motor. The extension usable with an electric drill motor was generally smooth so as not to snag things. The extension could not be easily gripped and turned as could a hand chuck extension. Thus, persons purchasing pin insertion tools had to choose to buy either a hand chuck or a power chuck or both. One could not buy a tool capable of both applications.